login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A034739 Dirichlet convolution of b_n=2^(n-1) with Catalan numbers. 0
1, 3, 6, 15, 30, 82, 196, 575, 1694, 5418, 17820, 60986, 212108, 751420, 2690912, 9728639, 35423206, 129779210, 477900844, 1767797906, 6565169652, 24468398788, 91486757944, 343068124346, 1289920924764, 4861980376004 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..26.

FORMULA

a(n) ~ 2^(2*n-2) / (sqrt(Pi) * n^(3/2)). - Vaclav Kotesovec, Sep 11 2019

MATHEMATICA

Table[Sum[CatalanNumber[n/d - 1]*2^(d - 1), {d, Divisors[n]}], {n, 1, 30}] (* Vaclav Kotesovec, Sep 10 2019 *)

CROSSREFS

Sequence in context: A242172 A126982 A256281 * A276670 A244706 A097941

Adjacent sequences:  A034736 A034737 A034738 * A034740 A034741 A034742

KEYWORD

nonn

AUTHOR

Erich Friedman

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 17 09:52 EST 2020. Contains 330949 sequences. (Running on oeis4.)